good air compressor...?

[EmilioG]

I'm shopping for a good small. portable, electric air compressor for my air powered
tools, i.e. 25K RPM die grinders, etc..
What would you recommend? I'd like it to be somewhat quiet and durable.
What do I look out for?
I will look at used as well.
Thanks

 

[xalky]

Cfm capacity is your benchmark. Look at the tools you'll be using and Thier corresponding cfm requirements. Add 30-50 percent extra and that's the size compressor you need. When in doubt, go bigger. You'll find that die grinders are very heavy on air requirements. You won't find a "small" air compressor that'll run a die grinder for very long.

 

[Dave Smith]

if you will be using die grinders and high cfm tools then a large(60-80) air tank is more important than the compressor, which should be at least 11cfm or higher.----Dave

 

[JimDawson]

To run a standard die grinder requires about 4.5 CFM @ 90PSI. So you are looking for a minimum of a 3HP compressor and it will run pretty continuously when running a die grinder. For commercial wood working use, I normally figure 5 HP for each air sander. If you want quiet, be prepared to spend a lot of money. They exist, but they are not cheap.

My 5HP (a true 5HP, not the ones that are said to be 5HP) runs about 50 % of the time when I'm using my die grinder.

A true 5HP compressor motor draws about 25 amps at 240V. Always look at the amp draw on the motor. Roughly 5 amps / HP @240V and 10 amps / HP @ 120V

Many of the so called ''5HP'' compressors have ''Special'' stamped on the motor data tag in place of an actual HP number. These are not 5HP compressors and I have see some that were actually closer to 1HP.

So having said all the above, HF is not a terrible place to buy a compressor, there are also the big box stores and farm supplies. If you are looking for used, Craigslist is a good resource. Just watch the HP rating.

 

[Mark in Indiana]

Look for an "industrial" compressor. Brands like Ingersoll Rand, Quincy, Gardener-Denver, etc. You will pay more, but you will only have to buy it once. I had a 2/hp. Ingersoll Rand for over 30 years. It ran everything from paint guns to sanders. Sanders were a little slow, but not unacceptable for my needs. The only reason that I no longer have it is because I traded up.


Happy Trails

 

[JeepsAndGuns]

Stay away from "oil less" compressors of any type. Running something that has a high demand of air like a die grinder is goona over heat and kill a oil less compressor in short order.
What you want is a belt driven cast iron oil type compressor. I really love my ingersoll rand model 242 compressor. Its on a 80 gallon tank and has a 5HP 230v motor running it. It holds up really nicely but even it cycles a good bit when I am doing some heavy die grinding.

Small and portable are not words for a compressor that can handle die grinders. If its small enough to transport easy, its going to be working hard to keep up with them, if it even can. If its big enough to handle them, its not gonna transport easy.

 

[Andre]

In the barn there is a 60 gallon CH compressor, the pause between pumping up's is around a minute with a HF pencil grinder. Die grinders use a ridiculous ammount of air. A pancake or hotdog compressor? Forget about it.....

 

[f350ca]

I have a Makita electric die grinder thats gone through two sets of bearings over the years. Had to buy an air operated one when one of the sets of bearings went and I had to wait for replacements but had to finish a job. The sound of a 5hp compressor running most of the time to feed it drove me nuts while thinking the electric one would be drawing 5 or 6 amps on 110 instead. Could never see the point of most air operated tools.

Greg

 

[fixit]

I'm shopping for a good small. portable, electric air compressor for my air powered
tools, i.e. 25K RPM die grinders, etc..
What would you recommend? I'd like it to be somewhat quiet and durable.
What do I look out for?
I will look at used as well.

Thanks

Do not buy a high speed (3450 PPM) compressor, they run hot & you end up with lots of water. They also have shorter life. I find for shop use a 5 hp 240 Volt 1740 (1800) RPM Motor, 3 or 4 cylinder pump turning about 750 RPM feeding a 60 to 80 gallon tank is about as good as you need. True bigger is better but 7,5 Hp & up really get expensive.

 

[GarageGuy]

As mentioned above, avoid oil-less compressors like the Plague. They are loud, and they die young. A belt driven cast iron compressor with an oil sump is quieter, pumps more air, and should last for decades.

Rather than trying to match a compressor to your initial air tool purchase, I recommend getting the largest compressor you can find in your price range. My reasoning is: you will always be getting more air tools. First are die grinders because they are cheap and handy, but soon you'll want sanders, grinders, impact wrenches, and even sand blasters. They are great tools, and you'll use the heck out of them. If you get a big compressor to start with, you won't be trying to upgrade in a year.

I bought what I *thought* was a big enough compressor. It was a 3HP twin cylinder with a 30 gal tank from the DIY store. It ran in the 90-120 lb air pressure range. It seemed like a big compressor until I really started to use it. Long story short, I was looking again within a year. I found a big used 220v 5HP stationary compressor with a 80 gallon tank for cheap that just whups up on any of the portable ones. I run 175 lbs of air pressure, and can sand blast continuously while the compressor cycles off to rest. Now I can get real work done.

Just my $.02

GG